Heat and mass transfer in impulse grain drying

Abstract

The technology of constant exposure to the grain with a drying agent is not optimal due to the fact that the grain overheats faster than moisture evaporates. It is necessary to lower the temperature of the drying agent to reduce the risk of deterioration in grain quality. Because of this, the performance of grain dryers with a constant heat supply is reduced. More promising is the drying technology with variable heat supply. The pulse mode is one of the varieties of the variable mode. This drying mode allows, while maintaining the passport performance of the dryers, to reduce the specific heat consumption. The purpose of the article is to calculate the pulse duration, pause and temperature of the drying agent. The duration of heating depends on the heat transfer coefficient, the physical and mechanical properties of the material and the logarithm of the temperature difference between the drying agent and the material. The duration of the deposit depends on the physical and mechanical properties of the material, the logarithm of the difference between the ratio of its moisture content and the diffusion coefficient. The article presents the characteristic features of heat and mass transfer and the main parameters of the process.

Keywords: drying; corn; heat and mass transfer; pulse mode; drying agent.